title: Suppression of β-catenin and cyclooxygenase-2 expression and cell proliferation in azoxymethane-induced colonic cancer in rats by rice bran phytic acid (PA).
abstract: BACKGROUND
  Phytic acid (PA) is a polyphosphorylated carbohydrate that can be found in high amounts in most cereals, legumes, nut oil, seeds and soy beans. It has been suggested to play a significant role in inhibition of colorectal cancer. This study was conducted to investigate expression changes of β-catenin and cyclooxygenase-2 (COX-2) and cell proliferation in the adenoma-carcinoma sequence after treatment with rice bran PA by immunocytochemistry.
  
  
  METHODS
  Seventy-two male Sprague-Dawley rats were divided into 6 equal groups with 12 rats in each group. For cancer induction two intraperitoneal injections of azoxymethane (AOM) were given at 15 mg/kg bodyweight over a 2-weeks period. During the post initiation phase, two different concentrations of PA, 0.2% (w/v) and 0.5% (w/v) were administered in the diet.
  
  
  RESULTS
  Results of β-catenin, COX-2 expressions and cell proliferation of Ki-67 showed a significant contribution in colonic cancer progression. For β-catenin and COX-2 expression, there was a significant difference between groups at p<0.05. With Ki-67, there was a statistically significant lowering the proliferating index as compared to AOM alone (p<0.05). A significant positive correlation (p=0.01) was noted between COX-2 expression and proliferation. Total β-catenin also demonstrated a significant positive linear relationship with total COX-2 (p=0.044).
  
  
  CONCLUSIONS
  This study indicated potential value of PA extracted from rice bran in reducing colonic cancer risk in rats.
authors.affiliation: UPM-MAKNA Cancer Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, Malaysia.
authors.forename: Norazalina
authors.initials: N
authors.lastname: Saad
authors.forename: Norhaizan Mohd
authors.initials: NM
authors.lastname: Esa
authors.forename: Hairuszah
authors.initials: H
authors.lastname: Ithnin
mesh_terms: D000236:Adenoma / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001397:Azoxymethane / Q000633:toxicity*; D015153:Blotting, Western; D002273:Carcinogens / Q000633:toxicity; D049109:Cell Proliferation / Q000187:drug effects; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control*; D051546:Cyclooxygenase 2 / Q000737:chemistry* / Q000378:metabolism; D007124:Immunoenzyme Techniques; D008297:Male; D012275:Oryza / Q000737:chemistry*; D010833:Phytic Acid / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D051176:beta Catenin / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D002273:Carcinogens; D051176:beta Catenin; D010833:Phytic Acid; D051546:Cyclooxygenase 2; D001397:Azoxymethane